1. Field of the Invention
The present invention relates to a photographic silver halide photosensitive material. More particularly, it relates to a photographic silver halide photosensitive material containing double merocyanine type sensitizing dyes having an improved solubility in organic solvents.
2. Description of the Prior Art
It has been well known that use of double merocyanine sensitizing dyes in a photographic silver halide photosensitive material can result in spectral sensitization. However, the serious defect in using double merocyanine sensitizing dye is its poor solubility. That is, with use of said dye, not only the dye solutions of desired concentration in organic solvents such as lower alcohol and acetone which are freely miscible with water cannot be obtained, but also the dye solutions even in organic solvents such as dimethylformamide cannot be obtained in satisfactory concentration. Therefore, in order to use the dye in an amount sufficient for spectral sensitization, it is necessary to use a large amount of dilute dye solution. As the result, it has often happened that properties of the photosensitive materials (such as mechanical strength of photosensitive film, adhesion between photosensitive layer and support, etc.) and photographic characteristics are unfavorably affected due to the use of a large amount of organic solvent.